Abstract des BISp

Es gilt als gesichert, dass dem Schlaf wesentliche Bedeutung für die physische und psychische Leistungsfähigkeit zukommt. Körperliche Aktivität wird vielfach als non-pharmakologische Intervention zur Verbesserung des Schlafs empfohlen. Bezüglich der Effekte von körperlicher Aktivität auf einzelne Schlafarchitektur- und Schlafkontinuitätsparameter existieren jedoch inkonsistente Befunde. Die vorliegende Arbeit setzt sich aus drei Experimenten zusammen. Die erste Studie untersuchte die Effekte von moderater und intensiver körperlicher Aktivität auf das Schlafverhalten von elf gesunden Kindern. Sie absolvierten zwei Belastungseinheiten auf dem Fahrradergometer. Diese fanden drei bis vier Stunden vor dem Schlafengehen statt, dauerten 30 Minuten und unterschieden sich nur in der Belastungsintensität. Die intensiven Belastungen (85 bis 90 Prozent der maximalen Herzfrequenz), nicht aber die moderaten (65 bis 70 Prozent der maximalen Herzfrequenz), resultierten in signifikant erhöhten Tiefschalfanteilen und einer erhöhten Schlafeffizienz. Vor dem Hintergrund der Annahme, dass metabolische Veränderungen im Gehirn in Verbindung mit der Belastungsintensität eine wesentliche Rolle in der Schlafregulation spielen, wurde in der zweiten Studie der Einfluss von moderater und intensiver Laufbandbelastung, sowie von drei- und fünfstündigem Schlaf und Schlafentzug auf den Gehirnstoffwechsel der adulten Ratte untersucht. Nur intensive Belastungen führten zu einer erhöhten Konzentration der schlaffördernden Substanz Adenosin, während die Schlafperioden reduzierte Adenosin- und Inosinkonzentrationen zur Folge hatten. Die Studie stützte die Annahme einer zentralen Rolle des Hirnsstoffwechsels in der Schlafregulation. Die dritte Studie untersuchte den Einfluss von akutem Computerspiel- und Fernsehkonsum auf das Schlafverhalten und die Gedächtnisleistung von Kindern. Der Computerspielkonsum resultierte in signifikant reduzierten Tiefschlafanteilen und Reduktionen der verbalen Gedächtnisleistung. Fernsehkonsum führte zu einer reduzierten Schlafeffizienz, hatte aber keinen Effekt auf Schlafarchitekturparameter. Messerschmidt

Abstract des Autors

In the last decade there has been enormous progress regarding the phenomenon of sleep. For centuries, sleep has been classified as a quite simple behavioural state, but today we appreciate that it is a complex and highly organized state with enormous importance for physical and mental health and performance. Sleep is important for mental and physical health and performance. In most discussions regarding sleep hygiene, exercise is considered as a non-pharmacological intervention to improve sleep. However, the current literature provides inconsistent and contrasting results regarding the effects of exercise on subsequent sleep. The variety of different methodology, age, gender, fitness level and body mass as well as time before sleep when exercise was completed makes it difficult to compare the results of these studies. Therefore it was first attempted to examine the effects of dynamic physical exercise on sleep patterns and vigilance state in humans using two standardized exercise sessions, which differed only in intensity. The results show for the first time that intensity of exercise is responsible for the effects on sleep architecture and sleep continuity parameters. Especially the amount of homeostatic regulated non-rapid eye-movement (NREM) slow-wave sleep (SWS) was significantly increased after exhaustive exercise, with an accompanied decrease in stage 2 sleep. In addition, significant increases in sleep efficiency as well as a decreased SOL were observed after high-intensity exercise. We conclude that intense exercise has a positive influence on sleep architecture and sleep continuity parameters in children, which support the capability of dynamic exercise as a non-pharmacological intervention in treatment against sleep disturbances which are highly prevalent in the general population. Because exercise intensity is responsible for subsequent changes in sleep, we hypothesized that metabolic changes in the human brain associated with exercise intensity may play a key role in regulation of sleep. Thus, we have attempted to clarify the influence of moderate and high-intensity exercise, sleep and sleep deprivation on nucleotide and nucleoside concentrations in the mammalian brain. Considering that the brain is one of the most active tissues in nucleoside and nucleotide syntheses and during ischemia metabolites are very unstable, we used freeze-clamp technique to freeze brain tissue immediately and prevent enzymatic activity. The results show that only high-intensity exercise leads to significant increases of the sleep-promoting substance adenosine, while sleep results in a progressive decline of these nucleosides with an accompanying increase of ADP and ATP in a temporal manner. We conclude that accumulation of the sleep-promoting substance adenosine after high-intensity exercise may be an important factor in homeostatic sleep regulation and that sleep could have an essential function in replenishment of high-energy phosphates. The study demonstrates for the first time that intensity of exercise is responsible for nucleoside changes in the mammalian brain, which are in accordance with the current hypothesis in the sleep research area that the brain energy metabolism is essential in sleep regulation, and it provides fundamental basics regarding the use of exercise in treatment against disturbances in sleep and alertness.
In the third study of the current thesis we examine the effects of singular excessive computer game and television exposure on sleep patterns and memory performance in school-aged children. The main results confirm the notion that computer game playing leads to significantly reduced amounts of slow-wave sleep as well as significant declines in verbal memory performance. Television exposure reduced sleep efficiency significantly but did not affect sleep patterns. Therefore, we conclude that excessive television and computer game consumption disrupt sleep and verbal memory performance in children, which supports the hypothesis of the negative influence of excessive media consumption on children’s sleep, health and development. Thus, the current thesis provides an insight regarding the relationship of exercise and sleep, accompanied by fundamental causes in brain energy metabolism, as well as the negative influence of media consumption on sleep and memory performance in children.